Many ores are metal oxides, which means the metal is combined with oxygen. To get the metal, the oxygen has to be removed from the ore. Removing oxygen is reduction, so the extraction of metals involves reduction of ores.
Iron is a good example. Iron oxide is heated with carbon: 2Fe2O3 + 3C → 4Fe + 3CO2. The iron oxide loses oxygen, so it is reduced to iron. The carbon gains oxygen to form carbon dioxide, so carbon is oxidised.
Whatever method is used to extract a metal, the metal compound in the ore is reduced to give the metal.